It may be necessary to adjust a length of an article, such as a ladder, when the ladder is located on uneven or on an incline surface. Use of a ladder on such a surface may pose a danger to a person climbing the ladder. In some situations it may be possible to level the contacting surface, for example, if the surface is dirt or gravel. However, levelling a dirt or gravel surface may be time consuming and unstable.
In some situations the surface may not easily be levelled, for example concrete surfaces including steps. In the past, placing wood blocks or other objects as spacers under a ladder leg have been used to adjust the length of one ladder leg to thereby level the ladder. However, using such temporary means tend to be unstable and may be unsafe as the blocks could shift relative to the ladder causing the ladder and user to fall. To overcome this problem, ladders and apparatus for adjusting ladders to be level on uneven or sloping surfaces have been developed.
A levelling apparatus attachable to a ladder to overcome the problems associated with temporary levelling means is described in PCT/AU02/00080. The described levelling apparatus comprises a tubular housing through which an inner leg telescopically moves to thereby adjust the extended length of the inner leg. The tubular housing is attachable to the ladder via a rod that extends at least partially through a rung of the ladder. Although this levelling apparatus provides a means for levelling a ladder, attaching and removing the levelling apparatus from a ladder can be time consuming. Accordingly, a user may leave the levelling apparatus attached to the ladder when not in use, which can lead to damage to the levelling apparatus, for example during transport and storage. Also, leaving the levelling apparatus attached to a ladder requires individual levelling apparatus for each ladder. This can be expensive, in particular in a situation where a person or company has multiple ladders.